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A/B drive swap switch

Posted: Sat Feb 10, 2018 6:33 pm
by Gunstick
Hi

There is an advantage to have drive A external to the ST as it allows to have a single Gotek/HxC to use on multiple STs.
Here are some infos about how to put a switch in the ST which changes the internal to external drive and vice/versa
https://rdemming.home.xs4all.nl/Atari/DriveSwapAtariST/

But it needs cutting YM pins or PCB traces. And today people try to avoid modding too much the old STs. So is there another solution?

Look at this page
http://info-coach.fr/atari/hardware/int ... _Connector
which says that you can put dirve0 signal onto the external connector instead of the drive1 signal. This is done on the W2 (STF) or W300/W301 (STE) soldering pads.



This means that selecting A will now switch to both external and internal drives, which obviously is bad.
But as the internal drive is on a ribbon cable, it should be not too difficult to make the internal get the drive1 signal.

One could put a header in there and have a switch somewhere.


STF
w2.png
w2.png (319.97 KiB) Viewed 3070 times

STE
w30w301.png
w30w301.png (189.67 KiB) Viewed 3070 times


Or dump the internal drive altogether and run A and B as external.

Re: A/B drive swap switch

Posted: Sun Feb 11, 2018 1:00 am
by exxos
You could try talking to petari nicely as he is doing a lot of mods to TOS lately, to see if a software patch could be done to swap AB.

Re: A/B drive swap switch

Posted: Thu Feb 15, 2018 12:34 am
by Gunstick
I guess an AUTO program can swap both drives when TOS/GEM is running. But for demo/games it's useless to change TOS, many switch off TOS and hammer around on the WD/YM directly.

Re: A/B drive swap switch

Posted: Fri Feb 23, 2018 11:04 pm
by Gunstick
here is schemata on how to make a drive switch using the available soldering pads
http://www.atari-forum.com/viewtopic.ph ... 10#p156680

also Troed did a "PCB trace cut" change himself and mad a nice blog post putting HxC and Floppy inside an STE
https://blog.troed.se/2014/10/21/atari- ... nd-b-swap/

I'm still thinking that it should be possible to have A/B switch and 2 drives inside without cutting pins or traces. I'll study that in some far away future...

Re: A/B drive swap switch

Posted: Tue Mar 06, 2018 10:37 pm
by tzok
It is possible for STf and STe and I have described it here: Drive swap on STe without cutting pins/tracks.

Re: A/B drive swap switch

Posted: Tue Mar 06, 2018 10:47 pm
by troed
tzok wrote:
Tue Mar 06, 2018 10:37 pm
It is possible for STf and STe and I have described it here: Drive swap on STe without cutting pins/tracks.
You're still cutting one trace though ... ?

Re: A/B drive swap switch

Posted: Sun Mar 11, 2018 9:03 pm
by tzok
I'm only cutting a bridge between jumpers, not really a trace.

Re: A/B drive swap switch

Posted: Mon Jun 11, 2018 11:19 pm
by ube
Been doing some thinking about this. One (less intrusive/more reversible) solution would be to desolder the YM and add a 4pdt IC (such as ts5v330) and an Attiny on an addon PCB. Then either having the attiny read reset at boot (connected to R100); hold reset at power on to swap A/B or having it connected to the GPO pin on the YM and make a binary to swap A/B by swapping state (can't remember right now if there's a pull-up or pull-down on the ST).

The latter solution would be 100% STE proof since the GPO isn't routed anywhere on the mobo, STs have it routed to pin 5(?) on the video out. But on the other hand; have anyone seen some hardware made to use that pin, ever?

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